The present invention relates generally to a sheet accumulating system and, more particularly, to a continuous web cutter for providing cut sheets and a right angle transport device for stacking the cut sheets.
Continuous web cutters are known in the art. Typically, a continuous web cutter is used to cut a continuous web of material into cut sheets, provide the cut sheets to a sheet accumulator and then to an insertion station in a mass mailing inserting system. As shown in FIG. 1, a continuous web of material with sprocket holes on both side of the web is fed from a fan-fold stack into the web cutter, which has two moving belts with sprockets (or tractors with pins) to move the web toward a guillotine cutting module for cutting the web cross-wise into separate sheets. Perforations are provided on each side of the web so that the sprocket hole sections of the web can be removed from the sheets prior to moving the cut sheets to other components of the mailing inserting system. In particular, the continuous web cutter, as shown in FIG. 1, is used to feed two webs of material linked by a center perforation. As shown, a splitter is used to split the linked webs into two separate webs before the webs are simultaneously cut by the cutting module into two cut sheets. The sheets are moved toward a right angle transport device so that the sheets are moved in a different direction, overlapping each other. Right angle transport devices are well known. For example, in U.S. Pat. No. 5,664,772, Auerbach et al. disclose a right angle transport device having two or more sheet turn-over modules, wherein the turn-over modules are placed at 45 degrees in the path of two or more sheets moving in a side-by-side fashion so that these sheets are turned over while their moving direction is changed by 90 degrees. As such, the sheets are moving substantially along the same line, with one sheet leading another in an overlapping manner. The overlapped mount by the two sheets using this type of right angle transport device is determined by the difference between the length and the width of the sheets. If the difference between the length and the width of the sheets is small, the overlapping between the two cut sheets may cause a paper jam when the sheets are collated into a stack in the sheet accumulator. Furthermore, with a small overlapped amount, a longer stacking mechanism must be used to collate the overlapped sheets into the stack. If the sheets are square or the length of the sheet is smaller than the width, then there is no overlapping when the sheets emerge from the right angle transport device.
It is advantageous and desirable to provide a method and device to increase the overlapped amount of the cut sheets as they exit the right angle transport device.
It is the primary object of the present invention to increase the overlapped amount of cut sheets in a continuous web cutter and a right angle transport device so as to increase the collating efficiency of a sheet accumulator. Accordingly, the first aspect of the invention is a continuous web cutter for cutting a web of material into groups of cut sheets, wherein each group of cut sheets comprises at least a first sheet and a second sheet, and wherein the first and second sheets are moved in a side-by-side fashion from the web cutter toward a right angle transport device for causing the first and second sheets to turn over while their moving direction is changed from a first direction to a second direction substantially perpendicular to the first direction, with the first sheet leading the second sheet in an overlapping manner, with an overlapped amount along the second direction. The web cutter comprises a first movement mechanism for moving the first sheet toward the right angle transport device with a first moving speed, and a second movement mechanism for moving the second sheet toward the right angle transport device with a second moving speed greater than the first moving speed for increasing the overlapped amount.
The second aspect of the present invention is a method of stacking sheets in a sheet accumulating system, including a right angle transport device, to change moving direction of sheets from a first direction to a second direction substantially perpendicular to the first direction, and a continuous web cutter for cutting a web of material into groups of cut sheets, wherein each group of cut sheets comprises at least a first sheet and a second sheet, and wherein the first and second sheets are moved substantially in a parallel fashion along the first direction from the web cutter toward the right angle transport device for causing the first and second sheets to turn over and move along the second direction, with the first sheet leading the second sheet in an overlapping fashion having an overlapped amount along the second direction. The method comprises the steps of providing a first movement mechanism for moving the first sheet with a first moving speed, and providing a second movement mechanism for moving the second sheet with a second moving speed greater than the first moving speed for increasing the overlapped amount.
The third aspect of the present invention is a sheet accumulating system, which comprises a right angle transport device to change moving direction of sheets from a first direction to a second direction substantially perpendicular to the first direction; a continuous web cutter for cutting a web of material into groups of cut sheets, wherein each group of cut sheets comprises at least a first sheet and a second sheet, and wherein the first and second sheets are moved along the first direct from the web cutter toward the right angle transport device for causing the first and second sheet to turn over and move along the second direction with the first sheet leading the second sheet in an overlapping fashion having an overlapped amount in the second direction; a first movement mechanism for moving the first sheet with a first moving speed; and a second movement mechanism for moving the second sheet with a second moving speed greater than the first moving speed for increasing the overlapped amount.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 2 to 8.